IC (integrated circuit) cards, which are all about the same width and length as a typical credit card, are designed for insertion into a slot of a card-receiving host which may lie in an electronic device such as a notebook computer. The PCMCIA (Personal Computer Memory Card International Association) currently specifies two logic voltages that are in general use, these being nominally three volts and five volts. Five volt cards require energization at about five volts and are designed to receive and generate digital signals of about five volts. Many newer electronic devices are able to use three volts in their logic circuits, which saves battery power, and are designed to operate with corresponding three volt IC cards.
At present, different host connectors, or hosts, are required for cards of different logic voltages. A high-voltage host will fully receive only a high-voltage card. A low voltage host will receive both high and low voltage cards, but the high voltage card will not operate when fully inserted. Low voltage cards cannot be inserted into high voltage hosts, because low voltage cards have a card discriminating key portion which will abut a barrier region in a high voltage host. It would be desirable if an electronic device and a single card host therein could fully receive and properly operate both high and low voltage cards.